
var fs = require('fs');
var readline = require('readline');
var {google} = require('googleapis');
var {GoogleAuth, OAuth2Client} = require('google-auth-library');

// If modifying these scopes, delete your previously saved credentials
// at ~/.credentials/google-apis-nodejs-quickstart.json
var SCOPES = ['https://www.googleapis.com/auth/youtube.force-ssl']
var TOKEN_DIR = (process.env.HOME || process.env.HOMEPATH ||
    process.env.USERPROFILE) + '/.credentials/';
var TOKEN_PATH = TOKEN_DIR + 'google-apis-nodejs-quickstart.json';
var oauth2Client = null;

// Load client secrets from a local file.
fs.readFile('client_secret.json', function processClientSecrets(err, content) {
  if (err) {
    console.log('Error loading client secret file: ' + err);
    return;
  }
  // Authorize a client with the loaded credentials, then call the YouTube API.
  //See full code sample for authorize() function code.
authorize(JSON.parse(content));
});

/**
 * Create an OAuth2 client with the given credentials, and then execute the
 * given callback function.
 *
 * @param {Object} credentials The authorization client credentials.
 * @param {function} callback The callback to call with the authorized client.
 */
function authorize(credentials) {
  var clientSecret = credentials.installed.client_secret;
  var clientId = credentials.installed.client_id;
  var redirectUrl = credentials.installed.redirect_uris[0];
  var auth = new GoogleAuth();
  oauth2Client = new OAuth2Client(clientId, clientSecret, redirectUrl);

  // Check if we have previously stored a token.
  fs.readFile(TOKEN_PATH, function(err, token) {
    if (err) {
      getNewToken(oauth2Client, requestData, callback);
    } else {
      oauth2Client.credentials = JSON.parse(token);
      console.log("shou quan cheng gong!!!");
    }
  });
}

/**
 * Get and store new token after prompting for user authorization, and then
 * execute the given callback with the authorized OAuth2 client.
 *
 * @param {google.auth.OAuth2} oauth2Client The OAuth2 client to get token for.
 * @param {getEventsCallback} callback The callback to call with the authorized
 *     client.
 */
function getNewToken(oauth2Client) {
  var authUrl = oauth2Client.generateAuthUrl({
    access_type: 'offline',
    scope: SCOPES
  });
  console.log('Authorize this app by visiting this url: ', authUrl);
  var rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
  });
  rl.question('Enter the code from that page here: ', function(code) {
    rl.close();
    oauth2Client.getToken(code, function(err, token) {
      if (err) {
        console.log('Error while trying to retrieve access token', err);
        return;
      }
      oauth2Client.credentials = token;
      storeToken(token);
    });
  });
}

/**
 * Store token to disk be used in later program executions.
 *
 * @param {Object} token The token to store to disk.
 */
function storeToken(token) {
  try {
    fs.mkdirSync(TOKEN_DIR);
  } catch (err) {
    if (err.code != 'EEXIST') {
      throw err;
    }
  }
  fs.writeFile(TOKEN_PATH, JSON.stringify(token));
  console.log('Token stored to ' + TOKEN_PATH);
}

/**
 * Remove parameters that do not have values.
 *
 * @param {Object} params A list of key-value pairs representing request
 *                        parameters and their values.
 * @return {Object} The params object minus parameters with no values set.
 */
function removeEmptyParameters(params) {
  for (var p in params) {
    if (!params[p] || params[p] == 'undefined') {
      delete params[p];
    }
  }
  return params;
}


function searchListByKeyword(auth, requestData) {
  var service = google.youtube('v3');
  var parameters = removeEmptyParameters(requestData['params']);
  parameters['auth'] = auth;
  service.search.list(parameters, function(err, response) {
    if (err) {
      console.log('The API returned an error: ' + err);
      return;
    }
    console.log(response);
  });
}


// setTimeout(() => {
//     searchListByKeyword(oauth2Client, {'params': {'maxResults': '25',
// 'part': 'snippet',
// 'q': 'surfing',
// 'type': ''}})
// }, 3000)

exports.youtubeAPI = google.youtube('v3');
exports.youtubeAuth = oauth2Client;
